There is a cellular phone which transmits phone book data automatically. For example, when a user carrying the cellular phone gets in a vehicle, the cellular phone enters a short range wireless communication area of an in-vehicle handsfree apparatus. When the cellular phone and the in-vehicle handsfree apparatus establish the communication link with each other, the cellular phone transmits the phone book data automatically to the in-vehicle handsfree apparatus (refer to Patent document 1).                Patent document 1: JP-2002-193046 A        
The following explains a case where a cellular phone transmits phone book data automatically by Bluetooth (registered trademark) communication.
A cellular phone compliant with PBAP (Phone Book Access Profile), which specifies automatic transmission of phone book data, can transmit phone book data automatically to the in-vehicle handsfree apparatus. In contrast, a cellular phone incompliant with PBAP cannot transmit phone book data automatically to the in-vehicle handsfree apparatus. Moreover, when phone book data are transmitted from the cellular phone, the in-vehicle handsfree apparatus stores and arranges the transmitted phone book data in the work memory device. When the user operates to demand a display of phone book data, the phone book data stored in the work memory device is displayed. The displayed phone book can be then searched for a phone number to make a phone call.
Thus, in the state where the cellular phone compliant with PBAP exists in the Bluetooth communication area of the in-vehicle handsfree apparatus, the newest phone book data stored in the cellular phone can be transmitted automatically to the in-vehicle handsfree apparatus and stored. The newest phone book data can be searched for a phone number to make a phone call.
In contrast, in the state where the cellular phone incompliant with PBAP exists in the Bluetooth communication area, the newest phone book data stored in the cellular phone cannot be transmitted automatically to the in-vehicle handsfree apparatus and stored. Therefore, if the user does not select transmitting the phone book data, the newest phone book data cannot be used for retrieving a phone number for making a phone call. This involves a disadvantage in usability.